FED-STD-228A
Method 1111.1
18 April 2014
THICKNESS, BRAID
1. SCOPE
1.1 This method is intended for use in determining the thickness of braids over the insulation of insulated
wire and cable.
2. SPECIMEN
2.1 The specimen should be a piece of the inspection unit at least 2 feet in length from which any
covering over the braid has been removed.
3. APPARATUS AND REAGENTS
3.1 The apparatus and reagents shall be as follows:
3.1.1 Micrometer caliper graduated to read in mils or 0.0001 inch and having flat surfaces on both anvil
and end of spindle, each approximately 0.25 inch in diameter. The surfaces of anvil and spindle shall be
parallel to within 0.0001 inch.
3.1.2 Wiping cloth.
3.1.3 Alcohol or other suitable solvent.
4. PROCEDURE
4.1 The specimen shall be free from mechanical damage. Any saturants or extraneous materials shall
be removed from the braid by means of the cloth and solvent. The micrometer caliper shall be applied
directly over the braid so that the specimen can just be moved between the anvil and spindle without
distortion of the braid. The diameter over the braid shall be read from the micrometer caliper scale and
the value recorded as D1.
4.2 The braid shall then be removed from the specimen and any saturants or other extraneous materials
removed from the surface of the core (assembly under the braid) by means of the cloth and solvent. The
diameter over the core shall then be determined as described for diameter over the braid and the value
recorded as D2. This measurement shall be made over the laps of tape or over the tops of any braid
marks in the insulation.
4.3 Three measurements equally spaced along the length of the specimen shall be made. The diameter
over the braid and over the core shall be determined as nearly as practicable at the same point.
4.4 If two braids are present, the thickness of the outer braid shall be determined from the diameter over
the inner braid.
4.5 In determining the thickness of the over-all braid of a twin-conductor cable, the diameter over the
core, D2 in 4.2, shall be equal to 1.64 times the diameter of the individual conductor.
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